Sonic 3 Complete is a hack of Sonic 3 & Knuckles by Tiddles. It began primarily as an alteration of the musical configuration of that game to to more closely resemble that of the original Sonic 3. It also contains bugfixes and other additional features. Recent versions provide additional patches to reverse some of these changes, or make others, to provide a version to match the player's own preference.

Initially developed privately for his own use, it was posted to the public in December 2009 following positive reaction to a similar hack posted by Hayate. Tiddles received Tech Membership for this hack not long after its initial release. Hayate's hack Sonic 3 Customizable is based upon the Sonic 3 Complete code, and bugfixes are shared between these hacks; however, Sonic 3 Customizable has not yet been updated with any Sonic 3 Complete changes since 2009, and hence does not contain every change listed here, though it contains additional features of its own.

Fixed spring artwork occasionally not being loaded for the Gumball Bonus Stage.

Knuckles no longer shifts forward a pixel when looking up.

The underwater character palette now reverts properly when Tails or Knuckles lose their super form.

It is no longer possible to gain additional lives for having 100 and 200 rings in the Lava Reef boss area if those lives were already earned earlier in act 2.

The Lava Reef and Death Egg boss areas will remember their starting timer if you die and restart (unless you die from a time over)

Robotnik's bald shine on the save screen is no longer red.

Stopped running animation being displayed in place of victory or super transform animation when in front of a solid object

The Launch Base music now only restarts once after Knuckles defeats the Act 1 boss.

Knuckles is no longer blocked from his normal Carnival Night exit when arriving from above

Drowning timer resets when turning hyper, along with music if necessary

The slot machine bonus stage now awards a continue through rings collected in the slot machine as well as around the sides.

Knuckles no longer turns into Sonic at the end of the slot machine bonus stage.

Various double jump fixes for Sonic, mostly involving unintentionally going into a slow bubble bounce by double jumping right before a bubble shield activated.

Fixed bug where a time over would not restart the starpost timer after continuing from a game over.

Fixed final Launch Base boss code to release Sonic from the arm after the boss is defeated - this was firing in the wrong situation, making Sonic always drop to standing after clearing the boss, but leaving him stuck if Tails killed the boss while Sonic was held.

Fixed occasional misalignment of continue screen

Fixed wrong tiles on Continue screen if you hit Game Over with Super/Hyper Sonic

Fire sprites no longer appear underwater in Angel Island

It is no longer possible to repeatedly double-jump in the Hydrocity fan tubes

Incorrect grabber arm sprite on DEZ final boss fixed - now uses the latched rather than open variant.

Fixed jittering screen lock after Marble Garden 1 miniboss

Workaround added to avoid occasional loss of music track change if requested during the 1up sting.

Debug: Hyper Knuckles can now wall smash when turned hyper by a monitor.

Debug: Tails' ring counter now falls in Doomsday.

Debug: Characters other than Sonic appear correctly in Doomsday.

Debug: Knuckles exits Doomsday to the title screen instead of a broken Sonic ending.

Features/misc.

Knuckles' introductory cutscene now plays in Angel Island rather than Sonic & Knuckles' Mushroom Hill, and feeds directly into the level rather than fading out and restarting.

The Mushroom Hill demo sequence now plays as one of the Sonic 3 demos.

Sonic's Angel Island intro can now be skipped using the button (only until Knuckles interjects).

For Super/Hyper forms to be invoked, you must press any button to jump, followed by a different button to double-jump.

To transform with debug mode enabled, you need to double-jump by pressing while is held down.

This allows Tails/Knuckles to play without powering up after having all emeralds.

Sonic can now transform even if he has a barrier.

Using the super transformation move while already transformed will allow you to turn back to normal.

While in super or hyper form, sped-up level music plays instead of invincibility music.

Super music changes now consistently have no effect during bosses.

Speed shoes monitors now have no effect when collected in super or hyper form.

You now need to collect 50 rings within the slot machine bonus stage itself to get a continue. (Can be patched back to the original setup)

Rings lost within the bonus stage will not take away from your collection total for the continue.

You can now do this in every slot machine bonus stage. Originally, you needed to wait until a new act or lose your rings in the main level.

Added a HUD element to the Slot Machine bonus stage to show progress towards a continue.

Added an extra cutscene after Launch Base, showing the Death Egg crashing, based on the Sonic Sonic & Knuckles Knuckles title screen.

After Hidden Palace, Knuckles is replaced by Robotnik on Sonic's continue screen

Added entries to Level Select for the Gumball Bonus Stage and the Hidden Palace Special Stage entryway.

New level select font, designed to be similar in style to the title card font.

Sound effect F3 will now speed up music as if speed shoes were active when used in the level select.

F4 returns to normal speed, as does starting another track.

Optional patches

A selection of patches has been provided to allow some of the hack's changes to be reversed, or provide alternative configurations, according to player preference. The following options are currently available:

Use the Sonic & Knuckles versions of the title screen, invincibility, game clear and 1UP tracks.

Use the Sonic & Knuckles version of only the 1UP track (overrides the above).

Use the Sonic & Knuckles midboss and Knuckles tracks exclusively. (Not compatible with the following patch)

Use the Sonic 3 midboss theme when fighting Knuckles only. (Not compatible with the previous patch)

Use the original Sonic & Knuckles credits music instead of the Sonic 3C0517 version.

Bring back the Sonic & Knuckles-style music fadeout before the results screen.

Resume Act 2's music after the zone results screen in cases where Sonic 3 & Knuckles did this.

Use the full set of Sonic 3 or Sonic & Knuckles level layouts.

Use the original Sonic 3 & Knuckles double-jump/transformation button setup (any double-jump invokes a super form transformation, if available, unless Sonic has a shield, which prevents transformation).

Use the original ending music (Sky Sanctuary instead of Sonic 3 Credits) - this can be set separately for Sonic's and Knuckles' endings.

Skip the new cutscene following Sonic and Tails' Launch Base

Start the Sonic 3 Credits music with the credit sequence (best used when the ending music has been changed back to Sky Sanctuary, otherwise the below patch is more useful) - this can be set separately for Sonic's and Knuckles' endings.

Allow the ending music to continue through both into the credits - this can be set separately for Sonic's and Knuckles' endings.

Revert to the original method of gaining continues from the slot machine bonus stage

Go back to using the invincibility music for super/hyper transformations. (It still doesn't play during a boss.)

Require 50 rings instead of 20 at a starpost to access a bonus stage, as in Sonic 3.

Always play Gumball bonus stages, as in Sonic 3.

The full set of these patches in IPS format can be downloaded in a separate archive below. Alternatively, an online customiser has been set up which allows for customisations to be selected and applied to a custom downloadable copy.